If you are being bullied on one of those social media platforms, contact each platform directly with the specific information regarding the nature of the bullying (who is doing it, what it involves, how long it's been going on, etc.) and ask them to intercede. You may also want to block bullying social media users if possible or delete your social media accounts altogether.
You said you made a mistake. What person hasn't made a mistake, even a huge one? Unfortunately, you are being shamed for yours in a very public way. Remember, however, the words of Eleanor Roosevelt -- that no one can make you feel inferior without your permission.